Solar tracking systems are systems in which one or more terrestrial solar cell arrays track the motion of the sun and convert sunlight into electrical energy. Accurate solar tracking is necessary because the amount of power generated by a given solar cell is related to the amount of sunlight that impinges on that solar cell. This is a particular concern for a concentrating solar cell array, which uses lenses to focus sunlight onto respective solar cells, because a tracking misalignment of only a few degrees can significantly reduce the amount of sunlight impinging on the solar cells and hence reduce the power output of the solar cells.
Solar tracking is achieved by properly orienting the solar array relative to the sun using motors and actuators to move the array (e.g., in roll and pitch or in azimuth and elevation directions) along a predetermined path that properly tracks movement of the sun. But tracking the sun means the motors and actuators, at least during the day, are in constant use. Not only that, but large solar arrays can mean that the motors and actuators must move large loads and are hence subjected to large loads themselves, so it is desirable to use motors and actuators that will have a suitably long lifetime under constant heavy loads.